Equipment racks of servers and other types of networking computers generally consist of line card modules, such as a printed circuit board (PCB). The line card modules can be inserted into the equipment racks to connect with a backplane. Typically, the equipment rack's chassis is configured to house many of these line cards. The limit of how big you can build the chassis with a single backplane depends on the size of that backplane. Further, the size of the backplane determines the number of line card modules that the chassis can hold. For example, a backplane of a certain height (e.g., 3 feet) can only hold so many line card modules. Some servers may include additional backplanes for attaching more line card modules. Other servers may use cables to connect additional line card modules to the backplane.